


HeadCanon Galore!

by Lady_Flame96



Category: Undertale (Video Game)
Genre: Alternate Universe, Alternate Universe - Horrortale (Undertale), Alternate Universe - Swapfell (Undertale), Alternate Universe - Underfell (Undertale), Alternate Universe - Underlust (Undertale), Alternate Universe - Underswap (Undertale), Drabble Collection, F/M, Headcanon, M/M, Multi, Nicknames, Valentine's Day, dating headcanos, fellswap red
Language: English
Status: In-Progress
Published: 2020-02-06
Updated: 2020-03-31
Packaged: 2021-02-28 01:07:37
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 7
Words: 2,979
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22585345
Author URL: https://archiveofourown.org/users/Lady_Flame96/pseuds/Lady_Flame96
Summary: Various Headcanons and scenarios with the skeletons from various AUs!Suggestions/Questions/Requests Open!
Relationships: Papyrus (Undertale)/Reader, Sans (Undertale)/Reader
Comments: 14
Kudos: 59





	1. Chapter 1

**Author's Note:**

> I just wanted to post something cute on Valentine's Day. I decided to make this "story" to post it and other short things.

Ehy guys!

I made this as a collection of cute drabbles!

If you have an idea for scenario or want to know about my headcanons for an AU, feel free to leave a comment!

Ex: "How would "X Skeleton" react to "X Event" ? Or What are your ideas about "X AU" ?

Ask about any AU! I don't know how many skeletons I'll be able to put in any scenario, but you guys feel free to ask!


	2. Dating HeadCanon!

**Summary for the Chapter:**

> Happy Valentine's day! Where would the bois take you for a date?

**Notes for the Chapter:**

> I still can't believe I wrote this in two hours!

**UT! Sans**

He would probably bring you to Grillby's. 

Don't call him lazy! He just feels safer there, in a familiar territory. Without the fear of people pointing and whispering at the two of you. 

But seriously, would you ever miss the opportunity to those famous burgers?

He even dressed nicely!

Plus Grillby is the best wingman!

* * *

**UF! Sans**

The Cinema. Is dark enough that he can cuddle you without people noticing. 

He might suggest to watch a horror or an action movie. Don't let him do that! It might trigger him!

If you opt for a comedy there's a chance you might get kicked out for how loudly he laugh. He'd laugh at the most stupid things.

He would enjoy a cartoon (Disney, Pixar, DreamWorks...) but he will never admit that. 

He secretly enjoys romantic movies. If you catch him crying he'll just make up excuses "this movie's so borin' it makes me cry."

If you suggest to watch a Marvel movie he might just ask you to marry him on the spot.

* * *

**US! Sans**

Everything is a date for him. Everything! 

Walking hands in hands? Date.

Chatting in his room? Date! 

That time you watched a movie with his brother, Undyne and Alphys? Definitely a date!

For him every moment you are together is a date! 

He would obviously make something super special for the important dates!

Getting a reservation at your favourite restaurant or buying you something that had been in your wishlist forever!   


What do you mean that's creepy? If you wanted privacy you should've been more careful about internet protection. 

* * *

  
**HT! Sans**

If food is involved he'll be happy. 

Maybe don't take him to a restaurant, too many people make him feel unsafe. 

Crowds makes his anxiety spike up. 

A nice dinner followed by a movie would be perfect! 

If he falls asleep don't get mad. He has lots of problems falling asleep. He has insomnia caused by his anxiety. 

Warning, he might grab you like a teddy bear in his sleep.

You make him feel safe.

* * *

**SF! Sans**

He would take you shopping. 

He would comment on how some clothes would be fitting only for a Queen/Lord. He will then bring you to a dressing room and shove to you the clothes he previously pointed out. Is his way to tell you how perfect you are in his eyes.

If you don't like shopping he'll just make fun with you of the weirdest / ugliest clothes you two were able to find. 

A blue sweater with "blueberry" in big letters? Hilarious!

That pink hoodie that said "ketchup"? Side-splitting!

  
You might just buy them as a prank gift for the others. 

* * *

  
**UL! Sans**

Please, please help this sweet lustful skeleton! He has no idea what he's doing! 

Probably a picnic would be ideal, intimate and far enough from people to let you chat in peace. 

Be careful with what you're talking about, he could ask you about your kinks with the same casualty of one's asking about the weather! 

Don't be mad at him, it was a normal to talk about back in his Underground! Explain to him the things that make you uncomfortable, he'll remember them.

  
He's a sucker for your "non-sexual touches"... AKA hugs.

**Notes for the Chapter:**

> Did you liked it? Do you have some ideas or scenes you would like to see? Wanna know my HeadCanons about an AU? Leave a comment!


	3. Food Intolerances

**Summary for the Chapter:**

> How would the "Chef" Skeletons react to a S/O who have a food intolerance.

**Notes for the Chapter:**

> I wrote this mostly for myself. Shoutout to all the food intolerant people out there!

**UT! Papyrus**

"WHAT DO YOU MEAN YOU CAN'T EAT MY SPAGHETTI?"

"I can't eat them because there's wheat in it."

"HOW ARE YOU EVEN ALIVE WITHOUT HAVING EVER EATEN SPAGHETTI IN YOUR LIFE?!"

"There are pasta made with gluten-free products, like rice or corn."

He seemed to ponder for a moment before suggesting to go together to the market to choose the ingredients and then cook together.

"FINALLY YOU'LL BE ABLE TO ENJOY THE CULINARY MASTERPIECE THAT IS MY SPAGHETTI! IS A SHAME THAT THEY HAD NO GLUTEN FREE GLITTER!" Yeah, a real shame.

* * *

**UF! Papyrus**

"OF COURSE YOU WEAK HUMANS CAN GET HURT EVEN BY FOOD!" He scoffed

"I'm sorry, I wish I could enjoy your lasagna but-" Before you could end your sentence he got up and left, leaving you alone in his dining room.

You left shortly after, feeling awkward to stay alone in _his_ house.

He called you and invited you over a couple of days later.

He placed a plate of lasagna in front of you "EAT." He ordered.

"But-" "EAT." You took a bite, seeing as there was no room for discussion.

Immediately the flavour of your favourite pasta mix invaded your mouth.

You looked at him but he was blushing and looking away. Your Sweet Tsundere Skeleton!

* * *

**US! Sans**

He was saddened at the thought that you were unable to eat various things. He hoped that his tacos weren't off limits for you.

"CAN YOU TELL ME WHAT EXACTLY YOU CAN'T EAT?"

After giving him a quick list he seemed to concentrated. "CAN YOU HELP ME CHECK THE INGREDIENTS OF MY TACO SHELLS? THEY SHOULD BE MADE OF CORN AFTER ALL!"

You two eagerly started searching in the ingredient list to see if you could eat the tacos. Turned out you could!

Unfortunately that didn't made up for Sans' terrible cooking. Your stomach screamed for vengeance!

* * *

**SF! Sans**

He was horrified at the thought that something _he_ made could harm you.

He glared at his burrito. How could he be so careless? So... stupid! He almost hurted you!

"Sans, is ok. You didn't knew." 

"NO! IS NOT OK! I ALMOST HURTED YOU! YOU KNOW I WOULD NEVER DO SUCH THING. YOU'RE THE LAST PERSON I WOULD EVER CAUSE HARM TO!"

You decided to try to stop his self-hate moment "I saw some burritos' ingredients in the gluten-free section. We could see if there are any that meet your standards!"

He seemed happy at your suggestion. He loves shopping afterall.

* * *

**HT! Papyrus**

He was terrified at the idea that _food_ of all things could hurt you. With his history any food was a blessing and the only thought that it could hurt you was causing him a panic attack.

In the Underground you couldn't be picky.

~~You would have died.~~

"Papyrus? Come back to me. Please. I'm sorry."

"No. It'S Ok.Is Not Your FAult Your Body Have Weird Tastes! I... I Want To Make SuperSpecial Food Just For You! Because We Have Plenty Of Food! And We Are On The Surface! N-No More Traps Or-"

"Papy, breath." He took a deep calming breath ~~even if he didn't need one~~ "You are right, you and your brother are on the Surface, safe and well fed. The nightmare is over." You said while caressing his skull.

He took your hand in his bigger one "I Know Darling, Because When I Look At You I Know That I Wouldn'T Have An Angel In My Nightmares."

Such a smooth skeleton.


	5. Weird Pets

**Summary for the Chapter:**

> How would the skeletons react to their S/O having an exotic pet?

**Notes for the Chapter:**

> This was requested by @Edgy_Alpaca ! Hope you like it!
> 
> Some of this are really short, but this are headcanons, not one shots after all.

**UT! Sans**

When you came home with a turtle in your hands he was more than a little surprised, but he couldn't denie that he became immediately fond of the tiny reptile. 

He feels like they are similar in some ways: slow but steady, only running for really important things (like food) and he wishes he was able to sleep for a whole season, but Papyrus would have his skull before letting him!

**UT! Papyrus**

He falls in love immediately with your chinchilla!

"LOOK AT IT! IS SO SOFT!" He was beaming while petting the animal "IS EVEN FLUFFIER THAN THAT ANNOYING DOG! AND IT DOESN'T EVEN TRY TO CHEW ON MY BONES!"

It surprised you how calm it reacted to Papyrus's booming voice, but he was probably too good with cuddles to run away. 

* * *

**UF! Sans**

He looked at your raccoon with wide sockets "if ya wanted som'thin' fluffy that loves trash ya just needed ta ask. i'd wear ma fluffiest jacket for ya."

He'll definitely call him Rocket!

**UF! Papyrus**

"WHAT IS THAT!"

"That's my pet."

"THAT IS NO PET!" Papyrus kept looking at your iguana dead in the eyes "IT'S CHALLENGING ME!"

"Papyrus, calm the F down!"

* * *

  
**Altertale Sans**

  
When you came home with what in your opinion was the cutest frog ever, at least according to you, he couldn't hide his excitement "How do you know that I love frogs?!"

He kept telling frog puns for the whole week.

* * *

  
**UL! Sans**

He took your python and placed it on his shoulders like a scarf.

"paint me like one of your french girls!" He said dramatically while the snake looks confused. He's all bones, how is he alive? Curious, it started to explore the skeleton whom paid it no mind.

When it reached the pelvis zone Sans stopped it "ah ah ah! that place is for your owner only" He said with a smirk and send a wink your way.

"Sans, you do-"

"i know, i know. you just look so cute when you are flustered." 

  
**UL! Papyrus**

Papyrus brought the ferret on his lap and stroked it's fur.

"THIS IS SUCH AN ELEGANT ANIMAL!"

"Really?"

"I SAW SOME PAINTINGS OF NOBLE HUMANS WITH THIS LITTLE CREATURE IN THEM! IT MUST BE SOME SORT OF ROYALTY!" 

(Now I'm picturing UL!Papyrus and UL!Mettaton going to visit museums together, as friends or as a couple, whatever you prefer!) 

**Notes for the Chapter:**

> I HAD to include Altertale Sans! He's such a cutie that doesn't get enough love!


	6. KIDS!

**Summary for the Chapter:**

> How would the skeletons react to their S/O having a child?
> 
> Requested by CupcakeAngel

**Notes for the Chapter:**

> This turned more into a "What would the skeleton do with a kid" but I hope you'll like it!

**UT! Sans**

At first, he was a bit scared that you already had someone special in your life, but he relaxed once he realised that that person was your kid.

To him, it wasn't a big deal. He could help your kid with homework, if they want to and most importantly "i can finally fulfil my dream... of telling dad jokes."

"SANS NO!"

"sans yes."

  
**UT! Papyrus**

He's not intimidated by your child. Is just another person he needs to show to that he's a fitting datemate!

  
What he would do with your kid? Two words: Giant Pillowfort!

You'll get back from work one day, Papyrus insisted on showing you his babysitting abilities, to find only pillows and tunnels made of covers! Where did they even found all those!

Another of the many mysteries of The Great Papyrus. 

**UF! Sans**

For a moment he thought that he was the "other man", right when he was actually falling for you.

His fears disappeared when he met your child. 

He became immediately hyper protective of your kid. Let's just hope that no one will ever bully your kid.

**UF! Papyrus**

He still had problems with showing his emotions freely to others. 

That won't stop him from playing whatever role your child had in mind!

He obviously rocked the villain role and the dashing hero one, but the real fun began when he was acting as the Princess!

"YOU CALL THAT A FIGHTING STANCE?! I COULD'VE DONE BETTER WITH MY HANDS TIED BEHIND MY BACK AND WITH HIGH HEELS! AND YOU ARE THE ONE SUPPOSED TO SAVE ME!?"

"YOU DIDN'T EVEN PREPARED YOUR VILLAIN MONOLOGUE!? I'VE BEEN KIDNAPPED BY AMATEURS!"

...it's a lot of fun. (He only criticised you because he knew you knew he was acting. He would never insult a kid!)

  
**US! Sans**

He wanted to help you at best as he could and he decided that cooking for you was his best option. 

When your kid offered to be his assistant, the stars in his eyes couldn't get bigger!

"Wait Chef! Don't punch the tomato!" Your kid said while holding the cookbook "The picture is different. See!"

"But Where Is The Passion? How Are We Supposed To Infuse Our Burning Passion In The Dish?"

"They say that if we cook with love, you can taste it in the dish!"

He doesn't have to ponder over who to think about. (Is You!) 

  
**US! Papyrus**

He doesn't care that you have a child. Monsters help each other out when a baby was born.

He would be happy to help you if you let him. He had a great teacher on how to care for a baby. 

He's extremely good at putting your toddler to sleep. Few lines of a story read with his honey-like voice and they stop crying and go right into dreamland.

  
**SF! Sans**

He's not putted off by you having an offspring. Of course someone else noticed you before he had the chance! You are just too amazing! 

He will prove to be a fitting mate!

"Can you help me with my homework?"

"IT'S EASY IF YOU DO IT THIS WAY. HOW DID THEY TAUGHT YOU TO DO THIS? UNBELIEVABLE! IF THEY DO NOT KNOW HOW TO TEACH, WHY ARE THEY EVEN TEACHING?!"

He always managed to boost your kid's ego.

  
**SF! Papyrus**

At first... he thought that your kid hated his guts. 

The first thing they said to him was "If you hurt them, I'll make you pay."

Until one night.

  
For a serie of reasons, he was sleeping at your place, on the couch. (He knew he wouldn't have been able to keep his hands to himself. You are too damn irresistible) He woke up from a nightmare, nothing new there, but when he was trying to calm down, your kid came into view with a panda plushie in their arms. He shove it into his arms saying "He always helps me when I have nightmares." 

He immediately disappeared from his sight.

They did care after all!

It's ok, he's used to deal with tsunderes. 

**HT! Sans**

He was scared.

He didn't wanted to scare your kid! 

The first thing your kid said was "Can he come with us for Halloween?"

But his (metaphorical) heart melted when they came to him to check for monsters under their bed.

He couldn't believe that they felt safe with him.

  
**HT! Papyrus**

He was afraid to scare your child or make them cry. He was a scary looking monster after all! 

But when you presented him as your boyfriend the kid's eyes widened "You are so cool!"

They loved to get piggy back rides from the tallest man possible! (I remember that as a kid I wanted to be on the tallest point possible!)

  
**UL! Sans**

He doesn't know anything about kids! 

Sure, he knew a lot about the process of making them, but that's it!

So, when you made him hold your baby he freaked out a little, not sure what to do, but your kid did! They loved his jacket's fur and to snuggle with it.

Sans was eager to learn! 

  
  
**UL! Papyrus**

Papyrus and your child had something in common: they're both eager to learn! 

  
Your kid insisted on bringing him to school. Apparently having your parent date a monster (or just dating somebody in general) was the coolest thing ever for the children! 

He loved the attention.


	7. Nicknames!

**Summary for the Chapter:**

> What would each skeleton call his S/O?

**UT! Sans**

Starlight (Because the thing he loves the most are stars)

  
**UT! Papyrus**

Dearest (because you are!)

**UF! Sans**

Sweetheart (He's not used to kindness and you're showing a lot to him.)

  
**UF! Papyrus**

He would call you Human when around others. (So no one will know that he cares)

He'll probably call you kitten since you're smaller than him and so adorable! 

  
**US! Sans**

Maiden (He wants to be your knight in shining armour bones!)

  
**US! Papyrus**

HoneyBee (Do I really have to explain this?)

  
**SF! Sans**

Pet in public (He doesn't want other monsters to know that he cares)

My Queen/My King or something related to royalty (he's your loyal knight and he will always protect you)

  
**SF! Papyrus**

Darling, because you are so precious! 

**HT! Sans**

Buttercup (it remind him not to try to eat you. He doesn't trust himself) 

**HT! Papyrus**

Angel (because that's what you must be for dating him!)

_**BONUS!** _

**Nightmare!**

Princess/Prince (He will make you his Queen/King of Darkness)


	8. **NSFW Headcanons**

**Summary for the Chapter:**

> What are the skeleton's kinks?

**Notes for the Chapter:**

> Avert your eyes young children!

**UT! Sans**

Definitely a sub. Not out of laziness, but because he loves to be taken care of. 

If you add some praises he could cum just from that! 

  
**UT! Papyrus**

He's a soft dom. He would never insult or hurt you even if you ask him to.

Lots of aftercare in any case!

  
**UF! Sans**

Big sub! Expect lots of biting! Little masochist. 

  
That being said, nothing would stop him from slamming you into a wall and fuck you roughly. 

**UF! Papyrus**

Big Dom! Might give you a collar.

Will hurt and insult if you both agreed on it.

**US! Sans**

Dom. Surprise surprise. Very happy to know that he is pleasuring you.

Kinda into bondage. 

**US! Papyrus**

Sub. He's gonna let you do all the work.

**SF! Sans**

Hella Dom! Degradation and bondage if previously accorded.

He would never hurt you if you don't like it! 

**SF! Papyrus**

Big Sub! If you have a leash and a whip, he will call you "master/mistress" in public. 

Expect lots of love bites.

**HT! Sans**

Breeding kink. Bites. 

He might cover you in ketchup, honey, chocolate or something similar and lick it off you. 

Pull at his dead socket or at his head wound if he starts to lose control. 

  
**HT! Papyrus**

He can't control his magic very well anymore sooo, he hopes you won't mind tentacles!

Get ready for lots of worshipping! 

_**BONUS!** _

  
**UL! Sans**

Every kink! Seriously! You could tell him that you like the nastiest stuff ever and he would talk about it as if it was the most normal thing to enjoy!

  
**Nightmare!**

He loves to feel you, either with his hands or his tentacles. 

Maybe he just likes the sight of you all tied up in his tentacles. 

**AlterTale Sans!**

He probably has a Daddy kink. 

He definitely has a breeding kink!

**Notes for the Chapter:**

> I don't know the names of some kinks, but these are my ideas. Don't judge me! Please.

**Author's Note:**

> Did you liked this? 
> 
> Come visit me on Tumblr! https://ladyflame-ask.tumblr.com/


End file.
